Robert A. Patzner
A main characteristic of the gobies is that the pelvic fins are
united and form a suction disc. An important difference to
the blennies (families Blenniidae and Tripterygiidae) is that the
dorsal fin D consists of two parts (one in the Blenniidae, 3 in
the Tripterygiidae). The anterior part D1 has mostly 6 hard rays, the
posterior part D2 consists of several soft rays.
The lateral line of gobies differs from that of most other fishes. It consists of single or rows of pores on the head and the anterior part of the body. Various degrees of reduction occur. Head and body show a species specific pattern of neuromast organs which are important for taxono-mical purposes.
The average age attained differs among goby species. Small species usually reach an age of one or two years. They spawn once and die thereafter. Large species can reach up to 10 years of age.
Mediterranean gobies (Gobiidae) inhabit many environments, from the shoreline down to a depth of more than 300 m . Most of the species lead a benthic life; however, some are free swimming (pelagic). Soft bottoms are colonized as well as hard bottoms and caves. Territoriality may be present.
Patterns are found with dots and spots some of them merging into longitudinal or crossing stripes. The back is darker than the belly. Some of the Mediterranean species are strongly coloured (e.g. yellow such as the golden goby, Gobius auratus), others have an intensive spawning colouration (e.g. black as in males of the black goby, Gobius niger). Several species can be identified using their live colouration.
Food and commercial value
Most Mediterranean gobies are predators which feed on small benthic animals such as polychaets, bivalves, gastropods, different crustaceans and small fish. Only a few are planktonic feeders. Most species are of no commercial value, only some large ones (especially Zosterisessor ophiocephalus are regularly found on fish markets.
There are many similarities with the family of Blenniidae (blennies) and other small benthic fish families. In some species the males have a special spawning colouration (e.g. Gobius niger, Fig. 1). Before spawning the males look for small cavities, crevices or other hiding places (Fig. 2). On sand, empty shells of bivalves are often used. From there they attract females to deposit their eggs on the walls or ceilings of their holes. The eggs of most gobies are oblong in shape and have anchor filaments on one of the poles (Fig. 3).
Several females spawn with one male. Only recently the mode of fertilization was discovered for one species: Zosterisessor ophiocephalus (see literature there). The male first releases sperm inside his cavity in the form of sperm trails on which the female deposits her eggs. From there the spermatozoa slide into the egg via the micropyle to fertilize it. It is not clear whether this is the case in all other goby species.
Until hatching the eggs are guarded by the male. The freshly hatched larvae swim freely for some days and feed on small zooplankton. After that they switch to their benthic life style.
Literature on reproductive biology can be found at literature of the single species.
Representatives of different animal groups seek shelter with sea urchins (e.g. polychaets, shrimps, amphipods, ophiurids). In the Mediterranean Sea beside these invertebrates one also can find juveniles of benthic teleost fishes together with the sea urchins Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis. Up to now the following species of gobies were found: Chromogobius zebratus, Gobius bucchichi, Millerigobius macrocephalus and Zebrus zebrus.
Association with anemones
immune to the strong poison of the snake lock anemone Anemonia
viridis. It can move among the tentacles bearing the nettle
cells and therefore is protected from predators. This association is
not a true symbiosis such as in tropical clown fishes because the
anemone gains no advantage from the presence of the goby. Usually the goby sits close to
the anemone but a direct contact with the tentacles is avoided. Only
when in danger the fish seeks shelter among the tentacles. If the
protecting mucous layer on the skin is removed (e.g. by hand) it
takes several days to regenerate. During this time the goby is
vulnerable to the anemone's sting. The association between fish and anemone is
different in different regions of the Mediterranean Sea. While in the
western part the partnership is obligatory, in the eastern
part it is much weaker and G. bucchichi is often found
without an anemone.
Links to other gobiid pages
Goby group: open to all those interested in the study of gobioid fishes. This would include, but is not limited to, systematists, ecologists, and physiologists. This unmoderated email group is for information and data exchange to further our understanding of gobioid fishes.
Gobiidae.com: Information on the gobioidea in the Americas - eastern Atlantic - parts of the Indo-Pacific.
Gobiidae in British Seas: Photographs and descriptions of the common intertidal gobies around the British Isles.
Gobioid Research Institute: Includes goby systematics, breeding gobies, distribution and identification of gobioid fishes of the Americas (database in progress), and an extensive bibliography. Also, opportunities for aquarists and students at home and in the field.
Goby frontiers: An image gallery with over 250 goby photographs, mostly taken by Japanese underwater photographers. Many striking and unusual gobies, some of them not commonly encountered by aquarists.
Goby movie clips: Short underwater clips of Indopacific gobies (in Japanese).
Goby company: Research group at the University of Vienna, Austria.
Larval gobies: Larval Gobiidae, Eleotrididae and the genus Ptereleotris from Carrie Bow Cay, Belize.
Larvae of gobies: Photographic guide to late-stage larvae of Gobiidae and other coral reef fishes.
The mudskipper: By Gianluca Polgar. Systematics and evolution, ecophysiology of an amphibious life, reproductive behaviour, and others.
Mudskipper World: Web site in Japanese, with a number of pictures and animations.
Richardís mudskipper and goby website: A website designed by Richard Mleczko of Australia. Includes a wealth of information on mudskippers, as well as some other goby species. (Not available in the web 07-2008)
Copyright © 2016 - Robert A. Patzner